U.S. Pat. Nos. 3,793,866 and 4,045,988, which are assigned to the assignee of the present invention, disclose forming machines of the type wherein a pair of dies are moved in opposite directions on opposite sides of a workpiece at a work station of the machine such that engagement of the dies with the workpiece provides forming thereof as the workpiece is rotated in synchronism with the moving dies. The machine disclosed by the U.S. Pat. No. 3,793,866 patent includes dies embodied by elongated racks that are movable rectilinearly in a spaced and parallel relationship to each other on opposite sides of the workpiece and in opposite directions as each other, while the machine disclosed by the U.S. Pat. No. 4,045,988 patent includes rotary dies that are supported on rotary spindles for rotation in opposite directions on opposite sides of the workpiece to provide the forming.
One type of loader conventionally utilized with forming machines includes a transfer beam that is moved in a manner so as to move workpieces into alignment with the machine work station for forming and thereafter out of alignment with the work station after the forming has taken place. This type of loader includes stationary supports spaced along the length of workpiece movement and movable supports spaced along the transfer beam. Upward movement of the transfer beam with the movable supports positioned below the stationary supports in alignment therewith lifts the workpieces upwardly from the stationary supports and horizontal movement of the beam then moves each workpiece into vertical alignment with the next stationary support whereupon downward movement of the transfer beam deposits each workpiece on the next stationary support. Horizontal movement of the transfer beam back to the original position completes the closed path of movement. A carrier receives each workpiece upon movement thereof into alignment with the machine work station. Movement of the carrier positions the workpiece for forming at the work station and thereafter moves the workpiece back into alignment with the other workpieces in preparation for the next cycle.
Transfer beams of this type of loader have previously been moved by a pair of cam units respectively located adjacent opposite ends of the transfer beam. Each cam unit has a single output that is connected to the adjacent end of the transfer beam and moved vertically and horizontally to provide the closed path of transfer beam movement that moves the workpieces along the spaced stationary supports by the movable supports carried on the transfer beam. Input shafts of the cam units are driven by an electric motor whose output shaft drives the input of a gear reducer. A pair of output shaft ends of the gear reducer are respectively connected to the input shafts of the cam units through a pair of torque limiters. Provision of the pair of torque limiters adds a substantial cost to the loader but is necessary in order to prevent overloading and possible damage if the transfer beam or one of the cam units should become mechanically stopped against movement.
Forming machine loaders of the transfer beam type have also previously been driven by pneumatic and hydraulic actuation. A linkage which supports the transfer beam with this type of actuation includes a pair of end levers having associated pivotal support axes respectively located adjacent opposite ends of the transfer beam. A pair of first arms of each end lever are connected to the adjacent beam end by roller type slide connections and a second arm of each lever is connected to a common drive link that is attached to a first cylinder of either the pneumatic or hydraulic type. Actuation of this first cylinder shifts the link to either vertically raise or lower the transfer beam depending upon the direction of the shifting. A second cylinder of either the pneumatic or hydraulic type extends between a central portion of the transfer beam and another arm of one of the end levers such that operation thereof shifts the beam horizontally in one direction or the other upon extension or retraction of the second cylinder. Both cylinders move during operation and thus must be connected to flexible conduits that supply the compressed air or pressurized hydraulic fluid for operating the cylinders.